__ on May Day,the Shanghai Expo has attracted tens of thousands of visitors around the world
问题描述：
__ on May Day,the Shanghai Expo has attracted tens of thousands of visitors around the world
解释答案用opened的原因
答
Until on May Day,the Shanghai Expo has attracted tens of thousands of visitors around the world
截止到五月一号,上海世博会已经吸引了世界各地数以万计的参观者.